Abstract Quantum discord has emerged as a robust diagnostic of nonclassical correlations beyond entanglement, particularly relevant for noisy intermediate-scale quantum (NISQ) devices. We present an experimental study of measurement-induced coherence-transfer (MICT) discord proxies implemented on IBM Quantum hardware and benchmarked against simulator results. Discord and coherence landscapes, collapse maps, fidelity maps, and histograms demonstrate that collapse domains remain identifiable despite gate errors and readout noise. Fidelity difference maps quantify deviations between hardware and simulator, while summary metrics establish reproducible benchmarks for discord/coherence suppression and resilience. These findings indicate that discord-related signatures persist as global, topology-informed features in the presence of realistic noise, positioning discord and measurement-induced coherence as practical diagnostics for NISQ benchmarking and quantum machine-learning pipelines.Abstract Quantum discord has emerged as a robust diagnostic of nonclassical correlations beyond entanglement, particularly relevant for noisy intermediate-scale quantum (NISQ) devices. We present an experimental study of measurement-induced coherence-transfer (MICT) discord proxies implemented on IBM Quantum hardware and benchmarked against simulator results. Discord and coherence landscapes, collapse maps, fidelity maps, and histograms demonstrate that collapse domains remain identifiable despite gate errors and readout noise. Fidelity difference maps quantify deviations between hardware and simulator, while summary metrics establish reproducible benchmarks for discord/coherence suppression and resilience. These findings indicate that discord-related signatures persist as global, topology-informed features in the presence of realistic noise, positioning discord and measurement-induced coherence as practical diagnostics for NISQ benchmarking and quantum machine-learning pipelines.

Aug 19, 20260 citations

Topology and Quantum Criticality: their interplay in one dimension

Ruben Verresen, Nick G. Jones, Roderich Moessner +1 more

Bulletin of the American Physical SocietyMar 8, 20180 citations

Universal signatures of Majorana zero modes in critical Kitaev chains

Nicolas Laflorencie

Many topological or critical aspects of the Kitaev chain are well known, with several classic results. In contrast, the study of the critical behavior of the strong Majorana zero modes (MZM) has been overlooked. Here we introduce two topological markers which, surprisingly, exhibit non-trivial signatures over the entire (1+1) Ising critical line. We first analytically compute the MZM fidelity ${\cal{F}}_{\rm MZM}$ --a measure of the MZM mapping between parity sectors. It takes a universal value along the (1+1) Ising critical line, ${\cal{F}}_{\rm MZM}=\sqrt{8}/π$ , independent of the energy. We also obtain an exact analytical result for the critical MZM occupation number ${\cal N}_{\rm MZM}$ which depends on the Catalan's constant ${\cal G}\approx 0.91596559$ , for both the ground-state ( ${\cal N}_{\rm MZM}=1/2-4{\cal{G}}/π^2\approx 0.12877$ ) and the first excited state ( ${\cal N}_{\rm MZM}=1/2+(8-4{\cal{G}})/π^2\approx 0.93934$ ). We further compute finite-size corrections which identically vanish for the special ratio $Δ/t=\sqrt{2}-1$ between pairing and hopping in the critical Kitaev chain.Many topological or critical aspects of the Kitaev chain are well known, with several classic results. In contrast, the study of the critical behavior of the strong Majorana zero modes (MZM) has been overlooked. Here we introduce two topological markers which, surprisingly, exhibit non-trivial signatures over the entire (1+1) Ising critical line. We first analytically compute the MZM fidelity ${\cal{F}}_{\rm MZM}$--a measure of the MZM mapping between parity sectors. It takes a universal value along the (1+1) Ising critical line, ${\cal{F}}_{\rm MZM}=\sqrt{8}/π$, independent of the energy. We also obtain an exact analytical result for the critical MZM occupation number ${\cal N}_{\rm MZM}$ which depends on the Catalan's constant ${\cal G}\approx 0.91596559$, for both the ground-state (${\cal N}_{\rm MZM}=1/2-4{\cal{G}}/π^2\approx 0.12877$) and the first excited state (${\cal N}_{\rm MZM}=1/2+(8-4{\cal{G}})/π^2\approx 0.93934$). We further compute finite-size corrections which identically vanish for the special ratio $Δ/t=\sqrt{2}-1$ between pairing and hopping in the critical Kitaev chain.

arXiv:2311.07571Nov 13, 20230 citations

Topological physics in quantum critical systems

Xue-Jia Yu, Limei Xu, Hai‐Qing Lin

arXiv:2601.00184Physics ReportsNov 16, 20257 citations

{\cal{F}}_{\rm MZM}

--a measure of the MZM mapping between parity sectors. It takes a universal value along the (1+1) Ising critical line,

{\cal{F}}_{\rm MZM}=\sqrt{8}/π

, independent of the energy. We also obtain an exact analytical result for the critical MZM occupation number

{\cal N}_{\rm MZM}

which depends on the Catalan's constant

{\cal G}\approx 0.91596559

, for both the ground-state (

{\cal N}_{\rm MZM}=1/2-4{\cal{G}}/π^2\approx 0.12877

) and the first excited state (

{\cal N}_{\rm MZM}=1/2+(8-4{\cal{G}})/π^2\approx 0.93934

). We further compute finite-size corrections which identically vanish for the special ratio

Δ/t=\sqrt{2}-1

between pairing and hopping in the critical Kitaev chain.